Tension tubing anchor



SEARCH @00M Z'Sheets-Sheet l FIDSO Sept. 24, 1963 w. P. oRR Erm.

TENSION TUBING ANCHOR Filed Deo. 19, 1960 #S 5 Ma. m.. nlv d l/ifiu w Nr 2 Lg 4 ,7 f Jmn /7 Y lo W k m 7 E N@ 2 -l mw. H 2 2- l N l 5 5 M H olo/ T6 T A A, L LT NT .l l. /f J 77 7 a v N u. J A u. H m. n 2 T5 2 M i l Sept. 24, 1963 w. P. oRR ErAL 3,104,708

TENSION TUBING ANCHOR Filed Deo. 19, 19Go 2 sheets-sheet 2 FIG.9. FIGJO. k/F'IC\.II. F'IG.|2. F'IGJB.

IN V EN TORS WILLIS P. ORR, BOBBY G. AGNEW,

BY wlLL/iya c. lNsEY,

ATTORNEY.

United States Patent O 3,104,708 TENSION TUBING ANCHOR Willis P. Orr, Tyler, Bobby G. Agnew, Monahans, and William C. Lindsey, Houston, Tex., assignors, by mesne assignments, to Jersey Production Research Company,

Tulsa, Okla., a corporation of Delaware Filed Dec. 19, 1960, Ser. No. 76,919 Claims. (Cl. 166-46) This invention concerns a collar locking, tension well pipe anchor tool. It also concerns a method for placing one pipe string in tension utilizing a collar recess of another surrounding pipe string.

It is advantageous and desirable for certain operations to have a well pipe string in tension. As an example, placing a pipe string in tension reduces the ourvatures in the pipe string, which in turn aids in running work-over tools into the well through the straightened pipe string. Also, placing a pipe string in tension during pumping operated by a string of sucker rods reduces breathing action of the pipe string, thereby lessenin-g sucker rod string wear.

Available well tools and known techniques for placing well pipes in tension are not satisfactory for smalldiameter pipes; e.g., ll/z-in. tubing inside 27A-in. casing, for they all require manipulation and setting of bulky slips designed to anchor the tubing to the casing. However, the present invention is satisfactory for use in smalldiameter pipe strings, and essentially it comprises a tubing anchor that can be set in and released from a casing collar recess. Also, the invention comprises a method for manipulating this anchor apparatus to place the tubing string in tension and for releasing tension on the tubing string.

Thus, a primary object of the present invention is to provide a full opening tubing string anchor. Another object of the invention is to provide a technique for placing the tubing string in tension by means of the anchor that does not require slips for engaging the casing string and that can be used with small-diameter pipe strings.

The above object and .other objects of the invention will be apparent from. the following more detailed description of the invention when taken in conjunction with the drawings wherein:

FIGS. 1-4 are fragmentary views of a well casing having arranged therein a tubing string upon which is mounted a tubing anchor assembly shown in various operative positions;

FIG. 5 is a view taken on lines 5-5 of FIG. 1;

FIG. 6 is a view taken on lines 6-6 of FIG. 1;

FIG. 7 is an enlarged view of the lower end of a collet finger;

FIG. 8 is a half-sectional view of a modied anchor assembly; and

FIGS. 9-14 are cross-sectional views of a casing string having a tubing string arranged within it upon which is mounted the anchor assembly shown in detail in FIGS. -1-6, illustrating a sequence of operations for anchoring the tubing in tension.

For a more detailed description of the invention, reference to the drawings in greater detail will now be made. In FIGS. 1-6 is shown a string of casing pipe 10, any two sections of which, as for example upper section 11 and lower section Y12, are coupled together by a pipe collar 13 to form a collar recess 14. Arranged in casing string is a mandrel or sub 15 connected in a tubing string 16 (see FIGS. 9-14) and provided with an exteriorly threaded portion 17, an annular groove 18, and a cone-shaped looking protuberance 19. A collar locking or anchoring assembly 20 is arranged on mandrel 15, and it includes a plurality of spaced-apart drag springs ice 21 adapted to frictionally engage the inner surface of casing section 11, an interiorly threaded portion 22 threadedly engaged with the threaded portion 17 of mandrel 15, and a plurality of spring or collet iinge-rs 23 (note FIG. 6 especially), each of which is provided at the ends thereof with a dog 24. A retainer ring 25, provided with a plurality of circumferentially spaced-apart and inwardly projecting lugs 27, is arranged in groove 18, as seen more clearly in FIG. 6.

The operation for anchoring tubing 16 as illustrated in FIGS. 1-4 is as follows. From the relative positions of mandrel 15 and anchoring assembly 20 shown in FIG. I1, mandrel l15 and tubing string 16 are rotated in a counterclockwise direction, which moves mandrel 15 upwardly relative to anchor assembly 20, since the position of anchoring assembly 20 is maintained stationary by drag springs 21. As seen in FIG. 2, as mandrel 15 moves upwardly relative to anchor assembly 20, collet ngers retainer ring 25 moves upwardly relative to its initial position on the collet iingers, thereby permitting dogs 24 on the lower ends of fingers 23 to move outwardly to contact casing section 12 while still located above locking cone 19. Tubing 16, mandrel 15, and anchor assembly 20 then are raised until dogs 24 move further outwardly and engage the lower end of casing section 11 in recess 14, as seen in FIG. 3. Then, as seen in FIG. 4, additional rotation of tubing 16 and mandrel 15 in a counterclock- 'Wise direction moves mandrel 15 further upwardly relative to anchor assembly 20 until the upper surface of locking cone 19 engages collet fingers 23 and locks them in recess 14.

When it is desired to release dogs `24 from engagement with collar recess 14, mandrel 15 and tubing string 16 are rotated in a clockwise direction, which moves mandrel 15 downwardly relative to anchor assembly 20, thereby moving locking cone 19 out of locking engagement with collet iingers 23 and retainer ring 25 downwardly on collet iingers 23 until the retainer ring reaches the position sho-wn in FIG. 1. In this position of retainer ring 25, ngers 23 are retracted a sufficient amount to permit mandrel 15 to be moved through casing string 10i. As a safety measure in the event mandrel 15 cannot be rotated clockwise relative to anchor assembly 20 because of sticking of the threads or other causes, dogs 24 may be connected to the ends of collet fingers 23 by means of shear pins 28, as illustrated in FIG. 7. By applying sufficient tensional force to tubing string 16, shear pins 28 fracture and release anchoring assembly 20 and mandrel I15 for removal from casing string 10.

An alternative apparatus is illustrated in FIG. 8. In this modication, a mandrel 30, provided with an exteriorl'y threaded portion 31, an exterior-ly ridged portion 32, and a tapered protuberance 33, is connected in a tubing string in a manner similar to tha-t described for FIGS.. l-6 inclusive. An anchoring assembly 34, prorvided with the same drag springs as in the previouslydescribed embodiment but not shown in FIG. 8, an interiorly screw-threaded portion 36 fthreadedly engaged with threaded portion 31, and resilient lingers or collets 37, is arranged on mandrel '30. `Fingers 37 are provided with ridges 38, which in the initial or retracted positions of fingers 37 tit on or mate with ridge 32, as well as dogs 39. The sequence of operation for latching dogs 39 in the casing string recess is similar to that described for the previous embodiment. Thus, mandrel 30' is rotated counterclockwise, which moves i-t upwardly relative to stationary anchor assembly 34, and disengages the mating ridges 32 and 38 to force fingers 37 and dogs 39 connected .thereto outward-ly to contact the casing pipe wall. Tubing 16 and mandrel 30 then are moved upwardly until dogs 39 are adjacent the pipe collar recess,

and continued rotation of mandrel 30 in a counterclockwise direction causes tapered protuberance 33 to engage lingers 37 and dogs 39 and lock them in the extended position in the collar recess. To release assembly 34, clockwise rotation of mandrel 30 moves it downwardly to release tapering protuberance 33 from engagement with fingers 37. Downward movement of mandrel 30 relative to assembly 34 is continued until ridges 32 and 38 again engage, as shown in FIG. 8, which permits retraction of dogs 39 from the collar recess of the casing string. As in the previous embodiment, dogs 39 may be connected to the lower ends of fingers 37 by means of a shear pin to insure release of the tubing string in the event clockwise rotation of the mandrel relative to the anchor assembly 34 is impossible. Ridge 32 on mandrel 30 preferably is designed to move fingers 37 outwardly `on the first two turns of mandrel 30 for collar locking and subsequent pipe spacing-out operations. Also, tapered portion 33 preferably is designed to collapse at a predetermined pull on mandrel 30 for an emergency release. This protuberance may be preformed or machined.

The full operation ofthe tool is shown in FIGS. 9-14 with reference to the embodiment of FIGS. 1-4. These figures show in addition to the elements previously described a wellhead 40` provided with a bowl surface 41, and in FIGS. 13 and 14 a wrap-around type anchor 42. The sequence of operation is as follows. Tubing string 16 is lowered in casing string 10 with mandrel 15 and anchor assembly 20 in the position shown in FIG. l; i.e., spring fingers 23 are held in retracted position by retainer ring 25 until dogs 24 are positioned below casing collar recess 14, the recess in which it is desired to anchor tubing 16 in tension. Then as illustrated in FIG. l0, tubing 16 and mandrel 15 are rotated in a counterclockwise direction a predetermined number of turns to release fingers 23 enough to permit dogs 24 to press or rub against the wall of section 12 of casing string 10 (see also FIG. 2). Tubing 16, mandrel 15, and anchor assembly 20 then are raised until dogs 24 engage the upper shoulder of collar recess 14, as illustrated in FIGS. 3 and 1l. A desired tension is applied to tubing 16,

out for hanging'tiibiiigi'lt in'vwiellheadhTlien, tension is released on tubing 16, and the tubing and mandrel are rotated counterclockwise, which moves mandrel `15 downwardly relative to anchor assembly and retracts fingers 23 to their position shown in FIGS. 1 and 9. Tubing 16 then is raised, and space-out pipe is added so that tubing 16 will hang in the wellhead at the desired tension, as illustrated in FIG. 12. Tubing 16 is lowered again until anchor assembly 20l is positioned as shown in FIG. 9, and the sequence of operations as described with regard to FIGS. 2 and 3 and 9 and l0 are repeated until dogs 24 are again engaged with the upper shoulder of collar recess 14. Then, extra tension, i.e., above the desired tension, is applied to tubing 16, and wraparound hanger 42 is installed on tubing string 16, as shown in FIG. 13. Thereafter, tubing 16 and mandrel 15 are rotated counterclockwise until locking cone 19 engages fingers 23 to lock dogs 24 in collar recess 14, and tubing 16 is supported in bowl 41 in wellhead 40 at the desired tension, as seen in FIG. 14. The equipment now is in position to install a Christmas tree or a pumping assembly.

To release anchor assembly 20 and remove tubing 16, fthe sequence of operations is reversed; i.e., tension is released on tubing 16, and it is rotated clockwise until locking cone 19 is disengaged from fingers 23, and the retainer ring is positioned on the lower portions of fingers 23, where they are in retracted position as shown in FIG. 1.

Having fully described the elements, nature, objects, and operation of our invention, we claim:

1. Apparatus for anchoring tubing string in a casing string collar recess in order to place the tubing string in tension comprising:

a mandrel arranged in said tubing string and having an externally screw threaded portion, an externally recessed portion below said scre'w threads, and an externally enlarged locking portion below said recess;

anchoring means arranged on said mandrel including drag springs adapted to frictionally engage the inner wall of said casing and prevent rotation of said anchoring means upon rotation of said mandrel, said drag springs having an internally screw threaded portion threaded to `the screw threads of said mandrel permitting longitudinal movement of said mandrel relative to said `anchoring means and a plurality of resilient, outwardly biased fingers, each provided witzltclngdgou'its lower end adapted to move outwardly -when unrestrained into a casing collar recess; and

a retainer ring arranged in the recess of said mandrel having portions of which surround and restrain the dogs of said resilient fingers from moving outwardly when said mandrel and anchoring means are ir one position relative to each other, and to permit said dogs to move outwardly adjacent the Wall of said casing and into said collar recess when said mandrel and anchoring means are positioned in a second position relative to each other and to move said enlarged locking portion of said mandrel upwardly to engage and -lock said dogs in said casing collar recess when said mandrel and anchoring means are positioned in a third position relative to each other.

2. Apparatus for anchoring a tubing string in a casing collar recess comprising:

a mandrel arranged in said tubing string;

anchoring means arranged on said mandrel and provided with outwardly and inwardly movable resilient casing collar recess latching means;

said anchoring means also including means engaging said oasing adapted to prevent rotation of said anchoring means upon rotation of said mandrel;

means on said mandrel and said anchoring means interconnecting said mandrel and said anchoring means adapted to permit upward and downward movement of said mandrel relative to said anchoring means when said mandrel is rotated in opposite directions, and rotation of said `anchoring means is prevented;

means arranged on both said anchoring means and said mandrel adapted to maintain said casing collar recess latching means in an inward position when said mandrel and anchoring means are in one axial position relative to each other, and to permit said casing collar recess latching means to extend to said casing wall and into said collar recess when said mandrel and anchoring means are in another axial position relative to each other; and

means on said mandrel adapted to engage said casing collar recess latching means to locking said latching means in said casing collar recess when said mandrel and anchoring means are in still another axial position relative to each other.

3. Apparatus as recited in claim 2 in which said collar recess latching means includes resilient fingers having do s releawsgtgywattached to the ends thereof.

Jhr

method for placing a tubing string in tension utilizing anchoring means arranged on said tubing string and adapted to engage a collar recess of a surrounding casing pipe string comprising the steps of:

lowering said tubing string until outwardly biased locking elements on said anchoring means are positioned below said collar recess; moving said locking elements outwardly to the casing pipe wall; raising said tubing string until said locking elements latch into and engage the upper end of said collar recess;

applying a desired tensional force to said tubing string;

max ijlmingmsaidwtulgingVstringmat the surface for spac- JNMing out for hanging said tubixig'string in the Wellhead;

releasing tension on said tubing string, and moving said locking elements inwardly from said collar recess;

raising said tubing and adding space-out pipe so that said tubing will land in the wellhead at a desired tension;

lowering said tubing string until the locking elements of said anchoring means are positioned below said collar recess;

moving said locking elements outwardly to the casing pipe wall;

raising said tubing string until said locking elements latch into said collar recess and engage the edge of pipe forming the upper end of said collar recess;

applying greater tensional force to said tubing string than said desired tensional force and installing a L hanger on said tubing string at the wellhead; and

then locking said elements in the collar recess, the tubing string being supported in the wellhead by the hanger at said desired tension.

5. Apparatus for anchoring a tubing string in a casing string collar recess in order to place the tubing string in tension comprising:

a mandrel arranged in said tubing string land having an externally screw threaded portion, an externally ridged portion below said screw threads, and an externally tapered locking portion below said ridged portion; and

anchoring means arranged ron said mandrel including drag springs adapted to frictionally engage the in-ner wall of said casing and prevent rotation of said anchoring means upon rotation of said mandrel, said drag springs having an internally screw threaded portion Ithreaded to the screw threads of said mandrel permitting longitudinal movement tof said mandrel relative to said anchoring means, a plurality 0f resilient fingers, 4each provided with a latching dog on its lower end a-dapted to move into a casing collar recess, and a recessed portion adapted to mate with the ridged portion of lsaid mandrel when said fingers are positioned inwardly whereby upward movement |of said mandrel relative to said anchoring means moves said rid-ged portion of said mandrel out of engagement with said recessed portion off said anchoring means causing thereby said fingers to move outwardly adjacent the wall of said casing and into Isaid collar recess, and further upward movement `of said mandrel relative to said anchoring means moves said tapered locking portion of said mandrel upwardly to engage and lock said dogs in said casing collar recess.

References Cited in the file of this patent UNITED STATES PATENTS 1,801,334 Dalldorf et al Apr. 21, 1931 2,613,746 Whitney Oct. 14, 1952 2,753,943 Morgan July 10, 1956 2,756,827 Farrar July 31, 1956 

4. A METHOD FOR PLACING A TUBING STRING IN TENSION UTILIZING ANCHORING MEANS ARRANGED ON SAID TUBING STRING AND ADAPTED TO ENGAGE A COLLAR RECESS OF A SURROUNDING CASING PIPE STRING COMPRISING THE STEPS OF: LOWERING SAID TUBING STRING UNTIL OUTWARDLY BIASED LOCKING ELEMENTS ON SAID ANCHORING MEANS ARE POSITIONED BELOW SAID COLLAR RECESS; MOVING SAID LOCKING ELEMENTS OUTWARDLY TO THE CASING PIPE WALL; RAISING SAID TUBING STRING UNTIL SAID LOCKING ELEMENTS LATCH INTO AND ENGAGE THE UPPER END OF SAID COLLAR RECESS; APPLYING A DESIRED TENSIONAL FORCE TO SAID TUBING STRING; MARKING SAID TUBING STRING AT THE SURFACE FOR SPACING OUT FOR HANGING SAID TUBING STRING IN THE WELLHEAD; RELEASING TENSION ON SAID TUBING STRING, AND MOVING SAID LOCKING ELEMENTS INWARDLY FROM SAID COLLAR RECESS; RAISING SAID TUBING AND ADDING SPACE-OUT PIPE SO THAT SAID TUBING WILL LAND IN THE WELLHEAD AT A DESIRED TENSION; LOWERING SAID TUBING STRING UNTIL THE LOCKING ELEMENTS OF SAID ANCHORING MEANS ARE POSITIONED BELOW SAID COLLAR RECESS; MOVING SAID LOCKING ELEMENTS OUTWARDLY TO THE CASING PIPE WALL; RAISING SAID TUBING STRING UNTIL SAID LOCKING ELEMENTS LATCH INTO SAID COLLAR RECESS AND ENGAGE THE EDGE OF PIPE FORMING THE UPPER END OF SAID COLLAR RECESS; APPLYING GREATER TENSIONAL FORCE TO SAID TUBING STRING THAN SAID DESIRED TENSIONAL FORCE AND INSTALLING A HANGER ON SAID TUBING STRING AT THE WELLHEAD; AND THEN LOCKING SAID ELEMENTS IN THE COLLAR RECESS, THE TUBING STRING BEING SUPPORTED IN THE WELLHEAD BY THE HANGER AT SAID DESIRED TENSION. 